1. Technical Field
Aspects of the present disclosure relate to an image forming apparatus, such as a copier, a printer, and a facsimile machine employing electrophotography.
2. Related Art
An electrophotographic image forming apparatus is known to primarily transfer multiple color toner images onto an intermediate transferor such that the color toner images are superimposed on one another on the intermediate transferor.
Such an image forming apparatus supplies a transfer bias to a recording medium while the recording medium passes between a secondary transfer roller (a transfer member) and an intermediate transferor (an image bearer), thereby secondarily transferring the superimposed toner images formed on the intermediate transferor onto the recording medium.
If the image bearer is in constant contact with the transfer member, a shock jitter occurs due to the impact generated when the recording medium enters and exits, thereby distorting the images. The term “shock jitter” used herein refers to the impact generated by a recording medium contacting an image bearer and transmitted to primary transfer portions between photoconductors and image bearers, thereby shifting the positions of the toner images on the image bearers when they are primarily transferred thereonto.
In order to prevent such shock jitter, the transfer member can be brought into contact with the image bearer as the recording medium passes between them. The image forming apparatus may then further cause the transfer member to separate from the image bearer as the recording medium exits.
However, such an image forming apparatus may exhibit uneven performance with respect to the prevention of shock jitter, the performance varying with the thicknesses of the recording media used.